Vane pump device

ABSTRACT

A vane pump includes: a rotor configured to rotate under rotational force from a rotary shaft while supporting multiple vanes and including a curved surface portion with an arc shape centered on the rotary shaft and a rotor recess depressed from the curved surface portion toward a rotation center; a cam ring disposed so as to surround the rotor and including an inner peripheral surface facing the curved surface portion of the rotor; and an inner plate disposed on one end of the cam ring in an axial direction of the rotary shaft so as to cover an opening of the cam ring and including a suction inner recess depressed toward the rotation center relative to the curved surface portion of the rotor.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a U.S. National Phase Application under 35 U.S.C. § 371 of International Patent Application No. PCT/JP2018/039212, filed October 22, 2018, which is incorporated herein by reference in its entirety. The International Application was published in Japanese on Apr. 30, 2020 as International Publication No. WO/2020/084666 under PCT Article 21(2).

FIELD OF THE INVENTION

The present invention relates to a vane pump device.

BACKGROUND OF THE INVENTION

Japanese Patent Application Laid-Open Publication No. 2013-050067 discloses a vane pump including: a rotor which is connected to a rotating shaft pivoted to an inner portion of a housing so as to rotate; a cam ring which is arranged in such a manner as to surround the rotor in the inner portion of the housing; a plurality of vanes which are slidably arranged in a plurality of vane grooves provided in a radial direction of the rotor; a plurality of pump chambers which are defined by the adjacent vanes around the rotor; and a plurality of discharge ports corresponding to the pump chambers carrying out a compression stroke, which are provided to be opposed in a diametrical direction of the rotor. In the vane pump disclosed in Japanese Patent Application Laid-Open Publication No. 2013-050067, the rotor is formed with recesses depressed from an outer peripheral surface thereof toward a rotation center.

CITATION LIST Patent Literature

-   Patent Literature 1: Japanese Patent Application Laid-Open     Publication No. 2013-050067

Technical Problem

To reduce viscosity of oil used as a working fluid of a vane pump, air bubbles (air) contained in the oil have been increasing. Suctioning of oil containing a large amount of air bubbles may lead to decrease in suction/discharge efficiency, fluctuation in discharge pressure, and aggravation of noise, for example. To suppress the decrease in suction/discharge efficiency and the like due to increase of air bubbles contained in the oil, one may conceive of reducing the capacity of pump chambers to thereby reduce an absolute amount of oil suctioned into the pump chambers. To achieve this, one may conceive of forming an outer peripheral surface of a rotor into an arc shape that is centered on the rotation center of the rotor. However, merely changing the outer peripheral surface of the rotor into an arc shape centered on the rotation center of the rotor to reduce the capacity of the pump chambers may lead to reduced suction efficiency and thus reduced pump performance.

An object of the present invention is to provide a vane pump device that can suppress decrease in pump performance while reducing the suctioned amount of air bubbles contained in a working fluid.

SUMMARY OF THE INVENTION Solution to Problem

With the above object in view, an aspect of the present invention is a vane pump device including: a rotor configured to rotate under rotational force from a rotary shaft while supporting a plurality of vanes, the rotor including a curved surface portion with an arc shape centered on the rotary shaft, the rotor including a first recess depressed from the curved surface portion toward a rotation center; a cam ring disposed so as to surround the rotor, the cam ring including an inner peripheral surface facing the curved surface portion of the rotor; and a one side member disposed on one end of the cam ring in an axial direction of the rotary shaft so as to cover an opening of the cam ring, the one side member including a second recess depressed toward the rotation center relative to the curved surface portion of the rotor.

Advantageous Effects of Invention

The present invention can provide a vane pump device that can suppress decrease in pump performance while reducing the suctioned amount of air bubbles contained in a working fluid.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of some of components of a vane pump as viewed from a cover side.

FIG. 2 is a perspective view of some of components of the vane pump as viewed from a case side.

FIG. 3 is a sectional view depicting a first oil channel in the vane pump.

FIG. 4 is a sectional view depicting a second oil channel in the vane pump.

FIG. 5 depicts a rotor, vanes, and a cam ring as viewed in one direction and in the other direction along a rotational axis direction.

FIG. 6 depicts a distance from a rotation center to a cam ring inner peripheral surface of the cam ring at each rotational angle.

FIG. 7 depicts an inner plate as viewed in the one direction and in the other direction along the rotational axis direction.

FIG. 8 depicts an outer plate as viewed in the other direction and in the one direction along the rotational axis direction.

FIG. 9 depicts a case as viewed in the one direction along the rotational axis direction.

FIG. 10 depicts the cam ring and the inner plate as viewed in the one direction.

FIG. 11 is a sectional view taken along a line XI-XI in FIG. 10.

FIG. 12 is a perspective view of the rotor, the multiple vanes, the cam ring, and the outer plate.

FIG. 13 depicts a schematic configuration of a suction inner portion of a vane pump of the second embodiment.

FIG. 14 depicts a schematic configuration of a suction inner portion of a vane pump of the third embodiment.

FIG. 15 depicts a schematic configuration of a suction inner portion of a vane pump of the fourth embodiment.

FIG. 16 depicts an inner plate of the fifth embodiment as viewed in the one direction and in the other direction along the rotational axis direction.

FIG. 17 depicts an outer plate of the fifth embodiment as viewed in the other direction and in the one direction along the rotational axis direction.

FIG. 18 depicts the cam ring and the inner plate as viewed in the one direction.

FIG. 19 depicts a modification of a rotor recess of the rotor.

FIG. 20 depicts a modification of a curved surface portion of the rotor.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention will be described below in detail with reference to the attached drawings.

First Embodiment

FIG. 1 is a perspective view of some of components of a vane pump device 1 (hereinafter referred to as a “vane pump 1”) of the embodiment as viewed from a cover 120 side.

FIG. 2 is a perspective view of some of components of the vane pump 1 as viewed from a case 110 side.

FIG. 3 is a sectional view depicting a first oil channel in the vane pump 1. FIG. 3 is also a sectional view taken along a line III-III in FIG. 5.

FIG. 4 is a sectional view depicting a second oil channel in the vane pump 1. FIG. 4 is also a sectional view taken along a line IV-IV in FIG. 5.

The vane pump 1 is a pump that is driven by, for example, power from an engine of a vehicle and supplies oil, which is an example of the working fluid, to apparatuses such as a hydraulic continuously variable transmission and a hydraulic power steering apparatus.

Also, the vane pump 1 suctions oil from a single suction inlet 116 and discharges it from two different discharge outlets of a first discharge outlet 117 and a second discharge outlet 118. Pressures of oil discharged from the first discharge outlet 117 and the second discharge outlet 118 may be either the same as or different from each other. More specifically, the vane pump 1 suctions oil from the suction inlet 116 into pump chambers through a first suction port 2 (see FIG. 3) and increases pressure of the oil in the pump chambers before discharging it to the outside from the first discharge outlet 117 through a first discharge port 4 (see FIG. 3). Additionally, the vane pump 1 suctions oil from the suction inlet 116 into the pump chambers through a second suction port 3 (see FIG. 4) and increases pressure of the oil in the pump chambers before discharging it to the outside from the second discharge outlet 118 through a second discharge port 5 (see FIG. 4). The first suction port 2, the second suction port 3, the first discharge port 4, and the second discharge port 5 are portions confronting (facing) the pump chambers.

The vane pump 1 includes a rotary shaft 10 that rotates under driving force from an engine of a vehicle or a motor, a rotor 20 that rotates along with the rotary shaft 10, multiple vanes 30 that are embedded in respective grooves formed in the rotor 20, and a cam ring 40 surrounding outer peripheries of the rotor 20 and the vanes 30.

The vane pump 1 further includes an inner plate 50 as an example of the one side member disposed at one end side of the rotary shaft 10 relative to the cam ring 40, and an outer plate 60 as an example of the other side member disposed at the other end side of the rotary shaft 10 relative to the cam ring 40.

The vane pump 1 further includes a housing 100 accommodating the rotor 20, the multiple vanes 30, the cam ring 40, the inner plate 50, and the outer plate 60. The housing 100 includes a closed-end cylindrical case 110 and a cover 120 closing an opening of the case 110.

<Configuration of the Rotary Shaft 10>

The rotary shaft 10 is rotatably supported by a case-side bearing 111 (described later) provided to the case 110 and a cover-side bearing 121 (described later) provided to the cover 120. The rotary shaft 10 is formed on its outer peripheral surface with a spline 11 and is connected to the rotor 20 via the spline 11. In the present embodiment, the rotary shaft 10 rotates under driving force of a driving source disposed outside of the vane pump 1, such as an engine of the vehicle, and rotates the rotor 20 via the spline 11.

In the vane pump 1 of the present embodiment, the rotary shaft 10 (the rotor 20) is configured to rotate in a clockwise direction in FIG. 1.

<Configuration of the Rotor 20>

FIG. 5 depicts the rotor 20, the vanes 30, and the cam ring 40 as viewed in one direction and in the other direction along the rotational axis direction.

The rotor 20 is a generally cylindrical member. The rotor 20 is formed on its inner peripheral surface with a spline 21 to be engaged with the spline 11 (see FIG. 1) of the rotary shaft 10. The rotor 20 includes on its outer periphery with curved surface portions 22 of an arc shape centered on a rotation center C of the rotary shaft 10. The rotor 20 is also formed on its outer periphery with vane grooves 23 depressed from the outer peripheral surface of the rotor 20 toward the rotation center C to accommodate the respective vanes 30. Multiple (ten in the present embodiment) vane grooves 23 are formed (radially) at equal intervals in the circumferential direction. The rotor 20 is also formed on its outer periphery with rotor recesses 24, which is an example of the first recess, depressed from the respective curved surface portions 22 toward the rotation center C.

Each curved surface portion 22 is formed between two adjacent vane grooves 23.

Each vane groove 23 is a groove that opens in the outer peripheral surface of the rotor 20 and also in both end surfaces of the rotor 20 in the rotational axis direction of the rotary shaft 10. When viewed in the rotational axis direction, as shown in FIG.5, the vane groove 23 has, on its outer periphery side, a rectangular shape whose longitudinal direction coincides with a radial direction and has, on its side closer to the rotation center C, a circular shape whose diameter is longer than a length of the rectangular shape in a transverse direction. In other words, the vane groove 23 has a cuboid groove 231 formed in a cuboid shape on its outer periphery side, and a columnar groove 232, which is an example of a center-side space, formed in a columnar shape on its side closer to the rotation center C.

The rotor recesses 24 are formed at respective ends of the rotor 20 in the rotational axis direction. Each rotor recess 24 is formed at the center of the corresponding curved surface portion 22 in the circumferential direction. A shape of the rotor recess 24 in the rotational axis direction is a chamfered shape such that the rotor recess 24 gradually approaches the rotation center C as it goes from the center side to the end side in the rotational axis direction.

<Configuration of the Vane 30>

Each vane 30 is a cuboid member and embedded into each one of the vane grooves 23 of the rotor 20. A length of the vane 30 in the radial direction is shorter than a length of the vane groove 23 in the radial direction, and the vane 30 has a narrower width than that of the vane groove 23. The vane 30 is held in the vane groove 23 such that the vane 30 can move in the radial direction.

<Configuration of the Cam Ring 40>

The cam ring 40 is a generally cylindrical member and includes a cam ring outer peripheral surface 41, a cam ring inner peripheral surface 42, an inner end surface 43 facing the inner plate 50 in the rotational axis direction, and an outer end surface 44 facing the outer plate 60 in the rotational axis direction.

When viewed in the rotational axis direction, the cam ring outer peripheral surface 41 has a substantially circular shape, in which a distance from the rotation center C to the cam ring outer peripheral surface 41 is substantially constant over the entire circumference thereof (except for a portion thereof), as shown in FIG. 5.

FIG. 6 depicts a distance L from the rotation center C to the cam ring inner peripheral surface 42 of the cam ring 40 at each rotational angle.

When viewed in the rotational axis direction, the cam ring inner peripheral surface 42 of the cam ring 40 is formed to have two heights in the distance L (i.e., the amount of protrusion of the vane 30 from the vane groove 23) from the rotation center C (see FIG. 5) at each rotational angle. That is, when a positive vertical axis in the view in the other direction in FIG. 5 is assumed to be at zero degrees, the distance L from the rotation center C gradually increases in an area between about 20 and 90 degrees in a counterclockwise direction and then gradually decreases in an area between about 90 and 160 degrees to thereby form a first height 42 a, and gradually increases in an area between about 200 and 270 degrees and then gradually decreases in an area between about 270 and 340 degrees to thereby form a second height 42 b. The two heights are of the same in the cam ring 40 of the present embodiment.

As shown in FIG. 5, the cam ring 40 includes multiple inner recesses 430 depressed from the inner end surface 43 and multiple outer recesses 440 depressed from the outer end surface 44.

As shown in FIG. 5, the inner recesses 430 include a first suction recess 431 constituting the first suction port 2, a second suction recess 432 constituting the second suction port 3, a first discharge recess 433 constituting the first discharge port 4, and a second discharge recess 434 constituting the second discharge port 5. When viewed in the rotational axis direction, the first suction recess 431 and the second suction recess 432 are formed to be point-symmetrical to each other about the rotation center C, and the first discharge recess 433 and the second discharge recess 434 are formed to be point-symmetrical to each other about the rotation center C. In the radial direction, the first suction recess 431 and the second suction recess 432 are depressed from the inner end surface 43 over the entire region thereof, and in the circumferential direction, the first suction recess 431 and the second suction recess 432 are depressed from the inner end surface 43 over a predetermined angular range. In the radial direction, the first discharge recess 433 and the second discharge recess 434 are depressed from the inner end surface 43 over a predetermined region thereof that extends from the cam ring inner peripheral surface 42 to some point toward the cam ring outer peripheral surface 41, and in the circumferential direction, the first discharge recess 433 and the second discharge recess 434 are depressed from the inner end surface 43 over a predetermined angular range. [0019]

As shown in the view in the one direction in FIG. 5, the outer recesses 440 include a first suction recess 441 constituting the first suction port 2, a second suction recess 442 constituting the second suction port 3, a first discharge recess 443 constituting the first discharge port 4, and a second discharge recess 444 constituting the second discharge port 5. When viewed in the rotational axis direction, the first suction recess 441 and the second suction recess 442 are formed to be point-symmetrical to each other about the rotation center C, and the first discharge recess 443 and the second discharge recess 444 are formed to be point-symmetrical to each other about the rotation center C. In the radial direction, the first suction recess 441 and the second suction recess 442 are depressed from the outer end surface 44 over the entire region thereof, and in the circumferential direction, the first suction recess 441 and the second suction recess 442 are depressed from the outer end surface 44 over a predetermined angular range. In the radial direction, the first discharge recess 443 and the second discharge recess 444 are depressed from the outer end surface 44 over a predetermined region thereof that extends from the cam ring inner peripheral surface 42 to some point toward the cam ring outer peripheral surface 41, and in the circumferential direction, the first discharge recess 443 and the second discharge recess 444 are depressed from the outer end surface 44 over a predetermined angular range.

When viewed in the direction of the rotational axis, the first suction recess 431 and the first suction recess 441 are provided at the same position, and the second suction recess 432 and the second suction recess 442 are provided at the same position. When the positive vertical axis in the view in the other direction in FIG. 5 is assumed to be at zero degrees, the second suction recess 432 and the second suction recess 442 are provided in an area between about 20 and 90 degrees in the counterclockwise direction, and the first suction recess 431 and the first suction recess 441 are provided in an area between about 200 and 270 degrees.

When viewed in the rotational axis direction, the first discharge recess 433 and the first discharge recess 443 are provided at the same position, and the second discharge recess 434 and the second discharge recess 444 are provided at the same position. When the positive vertical axis in the view in the other direction in FIG. 5 is assumed to be at zero degrees, the second discharge recess 434 and the second discharge recess 444 are provided in an area between about 130 and 175 degrees in the counterclockwise direction, and the first discharge recess 433 and the first discharge recess 443 are provided in an area between about 310 and 355 degrees.

The cam ring 40 is also formed with two first discharge through-holes 45 penetrating the cam ring 40 in the rotational axis direction so as to let the first discharge recess 433 and the first discharge recess 443 communicate with each other. The cam ring 40 is also formed with two second discharge through-holes 46 penetrating the cam ring 40 in the rotational axis direction so as to let the second discharge recess 434 and the second discharge recess 444 communicate with each other.

The cam ring 40 is also formed with a first through-hole 47 penetrating the cam ring 40 in the rotational axis direction so as to let the inner end surface 43 between the first suction recess 431 and the second discharge recess 434 and the outer end surface 44 between the first suction recess 441 and the second discharge recess 444 communicate with each other. The cam ring 40 is also formed with a second through-hole 48 penetrating the cam ring 40 in the rotational axis direction to let the inner end surface 43 between the second suction recess 432 and the first discharge recess 443 and the outer end surface 44 between the second suction recess 442 and the first discharge recess 443 communicate with each other.

<Configuration of the Inner Plate 50>

FIG. 7 depicts the inner plate 50 as viewed in the one direction and in the other direction along the rotational axis direction.

The inner plate 50 is a generally disk-like member with a through-hole formed at the center thereof. The inner plate 50 includes an inner plate outer peripheral surface 51, an inner plate inner peripheral surface 52, an inner plate cam ring-side end surface 53 facing the cam ring 40 in the rotational axis direction, and an inner plate non-cam ring-side end surface 54 that is an opposite end surface not facing the cam ring 40 in the rotational axis direction.

When viewed in the rotational axis direction, the inner plate outer peripheral surface 51 is circular as shown in FIG. 7, and a distance from the rotation center C to the inner plate outer peripheral surface 51 is substantially the same as a distance from the rotation center C to the cam ring outer peripheral surface 41 of the cam ring 40.

When viewed in the rotational axis direction, the inner plate inner peripheral surface 52 is circular as shown in FIG. 7, and a distance from the rotation center C to the inner plate inner peripheral surface 52 is substantially the same as a distance from the rotation center C to a bottom of the spline 21 (see FIG. 5) formed on the inner peripheral surface of the rotor 20.

The inner plate 50 includes inner plate cam ring-side recesses 530 including multiple recesses depressed from the inner plate cam ring-side end surface 53 and includes inner plate non-cam ring-side recesses 540 including multiple recesses depressed from the inner plate non-cam ring-side end surface 54.

The inner plate cam ring-side recesses 530 include a first suction recess 531 and a second suction recess 532. The first suction recess 531 is formed at a position facing the first suction recess 431 of the cam ring 40 and constitutes the first suction port 2. The second suction recess 532 is formed at a position facing the second suction recess 432 of the cam ring 40 and constitutes the second suction port 3. The first suction recess 531 and the second suction recess 532 are formed to be point-symmetrical to each other about the rotation center C.

The first suction recess 531 includes a first suction inner portion 538 that constitutes a portion of the first suction port 2 on its side closer to the rotation center C. The second suction recess 532 includes a second suction inner portion 539 that constitutes a portion of the second suction port 3 on its side closer to the rotation center C. These first suction inner portion 538 and second suction inner portion 539 will be described in detail later.

The inner plate cam ring-side recesses 530 further include a second discharge recess 533 formed at a position facing the second discharge recess 434 of the cam ring 40.

The inner plate cam ring-side recesses 530 further include an inner plate second recess 534 that is positioned to correspond to an area between the second suction recess 532 and the second discharge recess 533 in the circumferential direction and to face the columnar groove 232 of the vane groove 23 of the rotor 20 in the radial direction.

The inner plate cam ring-side recesses 530 further include an inner plate first recess 535 that is positioned to correspond to the first discharge recess 433 in the circumferential direction and to face the columnar groove 232 of the vane groove 23 of the rotor 20 in the radial direction.

The inner plate cam ring-side recesses 530 further include a first recess 536 that is positioned to face the first through-hole 47 of the cam ring 40 and a second recess 537 that is positioned to face the second through-hole 48 of the cam ring 40.

The inner plate non-cam ring-side recesses 540 includes an outer peripheral groove 541 and an inner peripheral groove 542. The outer peripheral groove 541 is formed along the outer periphery of the inner plate 50 to be fitted with an outer peripheral O-ring 57 (see FIG. 3). The inner peripheral groove 542 is formed along the inner periphery of the inner plate 50 to be fitted with an inner peripheral O-ring 58 (see FIG. 3). The outer peripheral O-ring 57 and the inner peripheral O-ring 58 each seal a gap between the inner plate 50 and the case 110.

The inner plate 50 further includes a first discharge through-hole 55 that penetrates the inner plate 50 in the rotational axis direction and is positioned to face the first discharge recess 443 of the cam ring 40. An opening of the first discharge through-hole 55 facing the cam ring 40 and an opening of the second discharge recess 533 are formed to be point-symmetrical to each other about the rotation center C.

The inner plate 50 further includes an inner plate first through-hole 56 that penetrates the inner plate 50 in the rotational axis direction and is positioned to correspond to the first suction recess 531 in the circumferential direction and to face the columnar groove 232 of the vane groove 23 of the rotor 20 in the radial direction.

<Configuration of the Outer Plate 60>

FIG. 8 depicts the outer plate 60 as viewed in the other direction and in the one direction along the rotational axis direction.

The outer plate 60 is a generally disk-like member with a through-hole formed at the center thereof. The outer plate 60 includes an outer plate outer peripheral surface 61, an outer plate inner peripheral surface 62, an outer plate cam ring-side end surface 63 facing the cam ring 40 in the rotational axis direction, and an outer plate non-cam ring-side end surface 64 that is an opposite end surface not facing the cam ring 40 in the rotational axis direction.

When viewed in the rotational axis direction, the outer plate outer peripheral surface 61 has a shape formed by cutting out two portions from a base circular shape, as shown in FIG. 8. A distance from the rotation center C to a periphery of the base circular shape is substantially the same as a distance from the rotation center C to the cam ring outer peripheral surface 41 of the cam ring 40. The two cutouts include a first suction cutout 611 that is positioned to face the first suction recess 441 and constitutes the first suction port 2, and a second suction cutout 612 that is positioned to face the second suction recess 442 and constitutes the second suction port 3. The outer plate outer peripheral surfaces 61 are formed to be point-symmetrical to each other about the rotation center C. The first suction cutout 611 and the second suction cutout 612 are formed to be point-symmetrical to each other about the rotation center C.

The first suction cutout 611 includes a first suction inner portion 613 that constitutes a portion of the first suction port 2 on its side closer to the rotation center C. The second suction cutout 612 includes a second suction inner portion 614 that constitutes a portion of the second suction port 3 on its side closer to the rotation center C. These first suction inner portion 613 and second suction inner portion 614 will be described in detail later.

When viewed in the rotational axis direction, the outer plate inner peripheral surface 62 is circular as shown in FIG. 8, and a distance from the rotation center C to the outer plate inner peripheral surface 62 is substantially the same as the distance from the rotation center C to the bottom of the spline 21 formed on the inner peripheral surface of the rotor 20.

The outer plate 60 includes outer plate cam ring-side recesses 630 including multiple recesses depressed from the outer plate cam ring-side end surface 63.

The outer plate cam ring-side recesses 630 include a first discharge recess 631 positioned to face the first discharge recess 443 of the cam ring 40.

The outer plate cam ring-side recesses 630 further include an outer plate first recess 632 that is positioned to correspond to an area between the first suction cutout 611 and the first discharge recess 631 in the circumferential direction and to face the columnar groove 232 of the vane groove 23 of the rotor 20 in the radial direction.

The outer plate cam ring-side recesses 630 further include an outer plate second recess 633 that is positioned to correspond to the second discharge recess 444 of the cam ring 40 in the circumferential direction and to face the columnar groove 232 of the vane groove 23 of the rotor 20 in the radial direction.

The outer plate cam ring-side recesses 630 further include a first V-shaped groove 634 that is parallel to the rotational axis direction, has a V-shaped cross-section along a plane perpendicular to the outer plate outer peripheral surface 61, and deepens as it goes from the upstream side to the downstream side in the rotational direction. A downstream-side end of the first V-shaped groove 634 is connected to an upstream-side end of the first discharge recess 631.

The outer plate cam ring-side recesses 630 further include a second V-shaped groove 635 that is parallel to the rotational axis direction, has a V-shaped cross-section along a plane perpendicular to the outer plate outer peripheral surface 61, and deepens as it goes from the upstream side to the downstream side in the rotational direction. A downstream-side end of the second V-shaped groove 635 is connected to an upstream-side end of a second discharge through-hole 65.

The outer plate 60 further includes a second discharge through-hole 65 that penetrates the outer plate 60 in the rotational axis direction and is positioned to face the second discharge recess 444 of the cam ring 40. An opening of the second discharge through-hole 65 facing the cam ring 40 and an opening of the first discharge recess 631 are formed to be point-symmetrical to each other about the rotation center C.

The outer plate 60 further includes an outer plate second through-hole 66 that penetrates the outer plate 60 in the rotational axis direction and is positioned to correspond to the second suction cutout 612 in the circumferential direction and to face the columnar groove 232 of the vane groove 23 of the rotor 20 in the radial direction.

The outer plate 60 further includes a first through-hole 67 and a second through-hole 68; the first through-hole 67 penetrates the outer plate 60 in the rotational axis direction and is positioned to face the first through-hole 47 of the cam ring 40, and the second through-hole 68 penetrates the outer plate 60 in the rotational axis direction and is positioned to face the second through-hole 48 of the cam ring 40.

<Configuration of the Housing 100>

The housing 100 accommodates the rotor 20, the vanes 30, the cam ring 40, the inner plate 50, and the outer plate 60. The housing 100 accommodates the one end of the rotary shaft 10 and lets the other end thereof protrude from the housing 100.

The case 110 and the cover 120 are tightened together with bolts.

(Configuration of the Case 110)

FIG. 9 depicts the case 110 as viewed in the one direction along the rotational axis direction.

The case 110 is a closed-end cylindrical member and includes, at the center of its bottom, a case-side bearing 111 that rotatably supports the one end of the rotary shaft 10.

The case 110 further includes an inner plate fitting portion 112 to which the inner plate 50 is fitted. The inner plate fitting portion 112 includes an inner diameter-side fitting portion 113 located close to the rotation center C (i.e., located on an inner diameter side) and an outer diameter-side fitting portion 114 located farther from the rotation center C (i.e., located on an outer diameter side).

As shown in FIG. 3, the inner diameter-side fitting portion 113 is provided on the outer diameter side of the case-side bearing 111 and includes an inner diameter-side cover portion 113 a covering a part of a periphery of the inner plate inner peripheral surface 52 of the inner plate 50 and an inner diameter-side restricting portion 113 b restricting the inner plate 50 from moving toward the bottom. When viewed in the rotational axis direction, the inner diameter-side cover portion 113 a has a circular shape in which a distance from the rotation center C to the inner diameter-side cover portion 113 a is shorter than the distance from the rotation center C to the inner plate inner peripheral surface 52. The inner diameter-side restricting portion 113 b has a donut-shaped surface perpendicular to the rotational axis direction. A distance from the rotation center C to an inner circle of the inner diameter-side restricting portion 113 b is the same as the distance from the rotation center C to the inner diameter-side cover portion 113 a, and a distance from the rotation center C to an outer circle of the inner diameter-side restricting portion 113 b is longer than the distance from the rotation center C to the inner plate inner peripheral surface 52.

As shown in FIG. 3, the outer diameter-side fitting portion 114 includes an outer diameter-side cover portion 114 a covering a part of a periphery of the inner plate outer peripheral surface 51 of the inner plate 50 and an outer diameter-side restricting portion 114 b restricting the inner plate 50 from moving toward the bottom. When viewed in the rotational axis direction, the outer diameter-side cover portion 114 a has a circular shape in which a distance from the rotation center C to the outer diameter-side cover portion 114 a is longer than a distance from the rotation center C to the inner plate outer peripheral surface 51. The outer diameter-side restricting portion 114 b has a donut-shaped surface perpendicular to the rotational axis direction. A distance from the rotation center C to an outer circle of the outer diameter-side restricting portion 114 b is the same as the distance from the rotation center C to the outer diameter-side cover portion 114 a, and a distance from the rotation center C to an inner circle of the outer diameter-side restricting portion 114 b is shorter than the distance from the rotation center C to the inner plate outer peripheral surface 51.

The inner plate 50 is inserted into the bottom of the case 110 until the inner peripheral O-ring 58, which is fitted to the inner peripheral groove 542 of the inner plate 50, abuts on the inner diameter-side restricting portion 113 b and the outer peripheral O-ring 57, which is fitted to the outer peripheral groove 541, abuts on the outer diameter-side restricting portion 114 b. Thus, the inner peripheral O-ring 58 contacts the inner peripheral groove 542 of the inner plate 50 and the inner diameter-side cover portion 113 a and the inner diameter-side restricting portion 113 b of the case 110 while the outer peripheral O-ring 57 contacts the outer peripheral groove 541 of the inner plate 50 and the outer diameter-side cover portion 114 a and the outer diameter-side restricting portion 114 b of the case 110. This seals the gap between the case 110 and the inner plate 50. As a result, a space inside the case 110 is partitioned into a space S1 closer to the opening of the case 110 than the inner plate fitting portion 112 and a space S2 closer to the bottom of the case 110 than the inner plate fitting portion 112. The space S1 closer to the opening of the case 110 than the inner plate fitting portion 112 constitutes a suction channel R1 for flow of oil suctioned from the first suction port 2 and the second suction port 3. The space S2 closer to the bottom of the case 110 than the inner plate fitting portion 112 forms a first discharge channel R2 for flow of oil discharged from the first discharge port 4.

Separately from the accommodation space for accommodating the rotor 20, the vanes 30, the cam ring 40, the inner plate 50, and the outer plate 60, the case 110 includes a case outer recess 115 that is located radially outside of the accommodation space and depressed from the opening side in the rotational axis direction. The case outer recess 115 faces a cover outer recess 123 (described later) formed in the cover 120 and constitutes a case second discharge channel R3 for flow of oil discharged from the second discharge port 5.

As shown in FIG. 1, the case 110 further includes a suction inlet 116 that lets the space 51 closer to the opening of the case 110 than the inner plate fitting portion 112 communicate with the outside of the case 110. The suction inlet 116 includes a columnar hole formed in a side wall of the case 110; a columnar direction of the hole is perpendicular to the rotational axis direction. The suction inlet 116 constitutes the suction channel R1 for flow of oil suctioned from the first suction port 2 and the second suction port 3.

As shown in FIG. 1, the case 110 further includes a first discharge outlet 117 that lets the space S2 closer to the bottom of the case 110 than the inner plate fitting portion 112 communicate with the outside of the case 110. The first discharge outlet 117 includes a columnar hole formed in the side wall of the case 110; a columnar direction of the hole is perpendicular to the rotational axis direction. The first discharge outlet 117 constitutes the first discharge channel R2 for flow of oil discharged from the first discharge port 4.

As shown in FIG. 1, the case 110 further includes a second discharge outlet 118 that lets the case outer recess 115 communicate with the outside of the case 110. The second discharge outlet 118 includes a columnar hole formed in a side wall of the case outer recess 115 of the case 110; a columnar direction of the hole is perpendicular to the rotational axis direction. The second discharge outlet 118 constitutes the case second discharge channel R3 for flow of oil discharged from the second discharge port 5.

(Configuration of the Cover 120)

As shown in FIG. 2, the cover 120 includes at its center a cover-side bearing 121 that rotatably supports the rotary shaft 10.

The cover 120 includes a cover second discharge recess 122 that is positioned to face the second discharge through-hole 65 and the outer plate second through-hole 66 of the outer plate 60 and depressed in the rotational axis direction from an end surface of the cover 120 facing the case 110.

The cover 120 further includes a cover outer recess 123 and a cover recess connecting portion 124. The cover outer recess 123 is positioned radially outside of the cover second discharge recess 122 and depressed in the rotational axis direction from the end surface of the cover 120 facing the case 110. The cover recess connecting portion 124 connects the cover second discharge recess 122 and the cover outer recess 123 at a position on the other direction side in the rotational axis direction relative to the end face of the cover 120 facing the case 110. The cover outer recess 123 opens at a position at which the cover outer recess 123 does not face the aforementioned accommodation space in the case 110 but faces the case outer recess 115. The cover second discharge recess 122, the cover recess connecting portion 124, and the cover outer recess 123 constitute a cover second discharge channel R4 (see FIG. 4) for flow of oil discharged from the second discharge port 5. Oil discharged from the second discharge port 5 flows into the case second discharge channel R3 via the cover recess connecting portion 124 and also flows into the outer plate second through-hole 66 via the cover second discharge recess 122.

The cover 120 further includes a cover suction recess 125 depressed in the rotational axis direction from the end surface of the cover 120 facing the case 110; in the cover 120, the cover suction recess 125 is positioned to face the first suction cutout 611 and the second suction cutout 612 of the outer plate 60 and to face a space that is within the space S1 closer to the opening of the case 110 than the inner plate fitting portion 112 and that is radially outside of the cam ring outer peripheral surface 41 of the cam ring 40.

The cover suction recess 125 constitutes the suction channel R1 for flow of oil suctioned from the suction inlet 116 into the pump chambers through the first suction port 2 and the second suction port 3.

The cover 120 further includes a first cover recess 127 and a second cover recess 128 depressed in the rotational axis direction from the end surface of the cover 120 facing the case 110; the first cover recess 127 and the second cover recess 128 are positioned to face the first through-hole 67 and the second through-hole 68, respectively, of the outer plate 60.

<Functions of the Vane Pump 1>

The vane pump 1 of the present embodiment includes ten vanes 30 and ten pump chambers. As the ten vanes 30 contact the cam ring inner peripheral surface 42 of the cam ring 40, each of the pump chambers is formed by two adjacent vanes 30, an outer peripheral surface of the rotor 20 between the two adjacent vanes 30, the cam ring inner peripheral surface 42 between the two adjacent vanes 30, the inner plate cam ring-side end surface 53 of the inner plate 50, and the outer plate cam ring-side end surface 63 of the outer plate 60. Taking a look at one pump chamber, the pump chamber makes one revolution around the rotary shaft 10 as the rotary shaft 10 makes one rotation and thus the rotor 20 makes one rotation. During one revolution of the pump chamber, oil suctioned from the first suction port 2 into the pump chamber is compressed and pressurized therein before being discharged from the first discharge port 4, and oil suctioned from the second suction port 3 into the pump chamber is compressed and pressurized therein before being discharged from the second discharge port 5.

<Shape of the Suction Inner Portion>

FIG. 10 depicts the cam ring 40 and the inner plate 50 as viewed in the one direction. FIG. 10 particularly depicts the first suction inner portion 538 of the inner plate 50.

FIG. 11 is a sectional view taken along the line XI-XI in FIG. 10. FIG. 12 is a perspective view of the rotor of the multiple vanes 30, the cam ring 40, and the outer plate 60.

Since the first suction inner portion 538 and the second suction inner portion 539 of the inner plate 50 and the first suction inner portion 613 and the second suction inner portion 614 of the outer plate 60 are substantially of the same shape, these may be collectively referred to as a “suction inner portion 710” in the following description. Also, when there is no need to distinguish between the first suction port 2 and the second suction port 3, the first suction port 2 and the second suction port 3 may be collectively referred to as a “suction port” in the following description.

The suction inner portion 710 includes a suction inner body 711 contoured to the shape of the curved surface portion 22 of the rotor 20, and a suction inner recess 712, which is an example of the second recess, depressed toward the rotation center C relative to the curved surface portion 22 of the rotor 20. The suction inner portion 710 further includes a suction inner intermediate portion 713 between the suction inner body 711 and the suction inner recess 712.

The suction inner body 711 has an arc shape centered on the rotation center C, and a distance from the rotation center C to the suction inner body 711 is the same as a distance from the rotation center C to the curved surface portion 22 of the rotor 20.

The suction inner recess 712 is formed to connect to an end of the suction port on the upstream side (upstream end). Taking the first suction port 2 as an example, a rotational angle of the end of the suction port on the upstream side (upstream end) is equal to a rotational angle of upstream ends of the first suction recess 431 and the first suction recess 441 of the cam ring 40, the first suction recess 531 of the inner plate 50, and the first suction cutout 611 of the outer plate 60, all of which constitute the first suction port 2, because the upstream ends of these portions all have the same rotational angle. In other words, the suction inner recess 712 of the first suction recess 531 is formed to connect to the upstream end of the first suction recess 531 of the inner plate 50.

A distance from the rotation center C to a portion of the suction inner recess 712 that is most depressed toward the rotation center C is equal to a distance from the rotation center C to an end of the rotor recess 24 of the rotor 20 in the rotational axis direction.

The suction inner intermediate portion 713 has a shape that is contoured to the shape of the inner peripheral surface of the cam ring 40. In other words, a distance from the rotation center C to the suction inner intermediate portion 713 at each rotational angle is shorter by a predetermined distance than a distance L from the rotation center C to the cam ring inner peripheral surface 42 of the cam ring 40 at each rotational angle.

The suction inner recess 712 and the upstream end of the suction port are connected at a curved surface of a predetermined radius, and the suction inner body 711 and the suction inner intermediate portion 713 are connected at a curved surface of a predetermined radius. The suction inner body 711 and a downstream end of the suction port are connected at a curved surface of a predetermined radius.

Below a description will be given of advantages of the vane pump 1 of the present embodiment in comparison with a comparative configuration.

As a vane pump of a comparative configuration, assume a configuration in which a recess depressed from the curved surface portion 22 toward the rotation center C is formed over the entire region of the curved surface portion 22 in the rotational axis direction, unlike the vane pump 1 of the present embodiment.

In the vane pump 1 of the present embodiment, the curved surface portion 22 formed between two adjacent vane grooves 23 has an arc shape centered on the rotation center C, and accordingly the vane pump 1 has a smaller pump chamber capacity as compared to the vane pump of the comparative configuration. The vane pump of the comparative configuration has a larger pump chamber capacity than that of the vane pump 1 of the present embodiment by the amount equal to the volume of the recess formed on the curved surface portion 22 over the entire region thereof in the rotational axis direction and depressed toward the rotation center C.

Hence, an amount of oil suctioned into the pump chambers of the vane pump 1 of the present embodiment is smaller than an amount of oil suctioned into pump chambers of the vane pump of the comparative configuration. As a result, an absolute amount of air bubbles (air) contained in the oil suctioned into the pump chambers of the vane pump 1 of the present embodiment is smaller than air bubbles suctioned into the pump chambers of the vane pump of the comparative configuration. If a large amount of air bubbles is suctioned into the pump chambers, a sound may occur as the air bubbles collapse in subsequent strokes. A sound may also occur as the air bubbles suctioned into the pump chambers are split or the split air bubbles hit the inner peripheral surface of the cam ring 40 and the like. Also, an amount of oil other than the air bubbles that can be suctioned into the pump chambers relative to the pump chamber capacity is reduced by the amount of air bubbles suctioned into the pump chambers, which means that suctioning of a large amount of air bubbles into the pump chambers may lead to a reduced suction/discharge efficiency or a fluctuation in discharge pressure. The vane pump 1 of the present embodiment can reduce the absolute amount of air bubbles suctioned into the pump chambers as compared to the vane pump of the comparative example, and thus can suppress a decrease in suction/discharge efficiency, a fluctuation in discharge pressure, and occurrence of noise.

Additionally, in the vane pump 1 of the present embodiment, the rotor recesses 24 depressed toward the rotation center C from each curved surface portion 22 are formed on respective ends of the rotor 20 in the rotational axis direction. The rotor recesses 24 facilitate suction of oil into the pump chambers as compared to a configuration without the rotor recesses 24. This increases the amount of oil suctioned into the pump chambers as compared to the configuration without the rotor recesses 24, increasing the suction efficiency. As a result, this can suppress an excessive decrease in the amount of oil suctioned into the pump chambers that may otherwise occur due to the outer periphery of the rotor 20 having the arc-like curved surface portion 22 centered on the rotation center C.

The rotor recesses 24 are formed on the ends of the rotor 20 in the rotational axis direction, which face the first suction recess 431 and the first suction recess 441 of the cam ring 40 located on the ends of the cam ring 40 in the rotational axis direction and constituting the suction port. This increases the amount of oil suctioned into the pump chambers as compared to, for example, a configuration in which the rotor recesses 24 are formed at the center of the rotor 20 in the rotational axis direction that does not face the first suction recess 431 and the first suction recess 441 of the cam ring 40.

The size of each rotor recess 24 in the rotational axis direction is smaller than that of the first suction recess 431 and the first suction recess 441 of the cam ring 40. This can reduce an absolute amount of air suctioned into the pump chambers while suppressing an excessive decrease in the amount of oil suctioned into the pump chambers that may otherwise occur due to the outer periphery of the rotor 20 having the arc-like curved surface portion 22 centered on the rotation center C.

In the vane pump 1 of the present embodiment, each rotor recess 24 of the rotor 20 is formed at the center of the curved surface portion 22 of the rotor 20 in the circumferential direction and is not formed near the vane groove 23. This increases an area of a portion of the rotor 20 for supporting the vane 30, as compared to a configuration in which the rotor recess 24 is also formed near the vane groove 23. This enables the rotor 20 to support the vane 30 over a wide area and thus helps avoid falling of the vane 30 even if the vane 30 is pushed by high-pressure oil flowing into the columnar groove 232 of the vane groove 23.

In the vane pump 1 of the present embodiment, the suction inner portion 710 (the first suction inner portion 538 and the second suction inner portion 539 of the inner plate 50 and the first suction inner portion 613 and the second suction inner portion 614 of the outer plate 60) of the suction port includes the suction inner recess 712 depressed toward the rotation center C relative to the curved surface portion 22 of the rotor 20. This shape increases an opening area of the suction port as compared to, for example, a configuration in which the suction inner body 711 is formed over the entire region of the suction inner portion 710 in the circumferential direction and the suction inner recess 712 is not formed. As a result, the vane pump 1 of the present embodiment can have increased suction efficiency as compared to a vane pump having the suction inner portion 710 that is not formed with the suction inner recess 712.

In the vane pump 1 of the present embodiment, the suction inner recess 712 is formed to connect to the upstream end of the suction port. This can increase the opening area of the suction port when the pump chamber capacity starts to increase during an initial phase of a suction stroke. As a result, the vane pump 1 of the present embodiment can increase the amount of oil suctioned therein and thus have increased suction efficiency.

At the downstream end of the suction port, where an amount of protrusion of the vane 30 from the vane groove 23 of the rotor 20 is large, the suction inner body 711, whose distance from the rotation center C is the same as the distance from the rotation center C to the curved surface portion 22 of the rotor 20, supports an end of the vane 30, and this helps avoid falling of the vane 30.

Second Embodiment

FIG. 13 depicts a schematic configuration of a suction inner portion 720 of a vane pump 702 of the second embodiment.

The vane pump 702 of the second embodiment differs from the vane pump 1 of the first embodiment in that the vane pump 702 includes a suction inner portion 720 that corresponds to the suction inner portion 710 of the vane pump 1 of the first embodiment. Below a description will be given of differences from the vane pump 1 of the first embodiment. The same structures and functions between the vane pump 702 of the second embodiment and the vane pump 1 of the first embodiment are denoted by the respective same reference numerals and detailed description thereof will be omitted.

The suction inner portion 720 includes a suction inner body 721 contoured to the shape of the curved surface portion 22 of the rotor 20, and a suction inner recess 722 depressed toward the rotation center C relative to the curved surface portion 22 of the rotor 20. The suction inner portion 720 further includes a suction inner intermediate portion 723 between the suction inner body 721 and the suction inner recess 722.

The suction inner recess 722 is formed to connect to an end of the suction port on the downstream side (downstream end). Taking the first suction port 2 as an example, a rotational angle of the end of the suction port on the downstream side (downstream end) is equal to a rotational angle of downstream ends of the first suction recess 431 and the first suction recess 441 of the cam ring 40, the first suction recess 531 of the inner plate 50, and the first suction cutout 611 of the outer plate 60, all of which constitute the first suction port 2, because the downstream ends of these portions all have the same rotational angle. In other words, the suction inner recess 722 in the first suction recess 531 is formed to connect to the downstream end of the first suction recess 531 of the inner plate 50.

A distance from the rotation center C to a portion of the suction inner recess 722 that is most depressed toward the rotation center C is equal to the distance from the rotation center C to the end of the rotor recess 24 of the rotor 20 in the rotational axis direction.

The suction inner intermediate portion 723 is formed to connect the suction inner recess 722 and a center portion 724 of the suction inner body 721 located between upstream and downstream ends of the suction inner portion 720.

The suction inner recess 722 and the downstream end of the suction port are connected at a curved surface of a predetermined radius, and the suction inner body 721 and the suction inner intermediate portion 723 are connected at a curved surface of a predetermined radius. The suction inner body 721 and an upstream end of the suction port are connected at a curved surface of a predetermined radius.

In the vane pump 702 of the second embodiment, the suction inner portion 720 (the first suction inner portion 538 and the second suction inner portion 539 of the inner plate 50 and the first suction inner portion 613 and the second suction inner portion 614 of the outer plate 60) of the suction port includes the suction inner recess 722 depressed toward the rotation center C relative to the curved surface portion 22 of the rotor 20. This shape increases an opening area of the suction port as compared to, for example, a configuration in which the suction inner body 721 is formed over the entire region of the suction inner portion 720 in the circumferential direction and the suction inner recess 722 is not formed. As a result, the vane pump 702 of the second embodiment can have increased suction efficiency as compared to a vane pump that is not formed with the suction inner recess 722.

In the vane pump 702 of the second embodiment, the suction inner recess 722 is formed to connect to the downstream end of the suction port. This can increase the opening area of the suction port when the pump chamber capacity almost reaches a maximum. As a result, the vane pump 702 of the second embodiment can increase the amount of oil suctioned therein and thus have increased suction efficiency.

Third Embodiment

FIG. 14 depicts a schematic configuration of a suction inner portion 730 of a vane pump 703 of the third embodiment.

The vane pump 703 of the third embodiment differs from the vane pump 1 of the first embodiment in that the vane pump 703 includes a suction inner portion 730 that corresponds to the suction inner portion 710 of the vane pump 1 of the first embodiment. Below a description will be given of differences from the vane pump 1 of the first embodiment. The same structures and functions between the vane pump 703 of the third embodiment and the vane pump 1 of the first embodiment are denoted by the respective same reference numerals and detailed description thereof will be omitted.

The suction inner portion 730 of the third embodiment differs from the suction inner portion 710 of the first embodiment and the suction inner portion 720 of the second embodiment in that a suction inner recess 732 that is most depressed toward the rotation center C is formed at the center of the suction inner portion 730 between upstream and downstream ends thereof. A distance from the rotation center C to a portion of the suction inner recess 732 that is most depressed toward the rotation center C is equal to the distance from the rotation center C to the end of the rotor recess 24 of the rotor 20 in the rotational axis direction.

The suction inner portion 730 further includes an upstream-side connecting portion 735 that connects the suction inner recess 732 and an upstream point 734. The upstream point 734 is located at the upstream end of the suction inner portion 730, and a distance from the rotation center C to the upstream point 734 is equal to the distance from the rotation center C to the curved surface portion 22 of the rotor 20. The suction inner portion 730 further includes a downstream-side connecting portion 737 that connects the suction inner recess 732 and a downstream point 736. The downstream point 736 is located at the downstream end of the suction inner portion 730, and a distance from the rotation center C to the downstream point 736 is equal to the distance from the rotation center C to the curved surface portion 22 of the rotor 20.

The upstream-side connecting portion 735 and the upstream end of the suction port are connected at a curved surface of a predetermined radius, and the downstream-side connecting portion 737 and the downstream end of the suction port are connected at a curved surface of a predetermined radius.

In the vane pump 703 of the third embodiment, the suction inner portion 730 (the first suction inner portion 538 and the second suction inner portion 539 of the inner plate 50 and the first suction inner portion 613 and the second suction inner portion 614 of the outer plate 60) of the suction port includes the suction inner recess 732 depressed toward the rotation center C relative to the curved surface portion 22 of the rotor 20. This shape increases an opening area of the suction port as compared to, for example, a configuration in which a distance from the rotation center C to any point on the suction inner portion 730 in the circumferential direction is the same as the distance from the rotation center C to the curved surface portion 22 of the rotor 20. As a result, the vane pump 703 of the third embodiment can have increased suction efficiency as compared to a vane pump that is not formed with the suction inner recess 732.

In the vane pump 703 of the third embodiment, the suction inner recess 732 is formed at the center in the circumferential direction of the suction inner portion 730 of the suction port. This can increase the opening area of the suction port when the pump chamber capacity starts to increase and then the rotor 20 rotates by about 7 to 45 degrees. This can increase the opening area of the suction port immediately after the start of suctioning in a high rotation speed range of the rotor 20 in which the vane pump 703 starts suctioning the oil only after the rotor 20 have rotated by, e.g., about 5 degrees after the start of increase in the pump chamber capacity. This leads to increased suction efficiency.

At the downstream end of the suction port, where an amount of protrusion of the vane 30 from the vane groove 23 of the rotor 20 is large, a distance from the rotation center C gradually increases from the upstream end side to the downstream end. This makes it easy to support the end of the vane 30 and thus helps avoid falling of the vane 30.

Fourth Embodiment

FIG. 15 depicts a schematic configuration of a suction inner portion 740 of a vane pump 704 of the fourth embodiment.

The vane pump 704 of the fourth embodiment differs from the vane pump 1 of the first embodiment in that the vane pump 704 includes a suction inner portion 740 that corresponds to the suction inner portion 710 of the vane pump 1 of the first embodiment. Below a description will be given of differences from the vane pump 1 of the first embodiment. The same structures and functions between the vane pump 704 of the fourth embodiment and the vane pump 1 of the first embodiment are denoted by the respective same reference numerals and detailed description thereof will be omitted.

The suction inner portion 740 of the fourth embodiment differs from the suction inner portion 710 of the first embodiment in that a portion corresponding to the suction inner recess 712 of the suction inner portion 710 of the first embodiment is formed over the entire suction inner portion 740 that constitutes a portion of the suction port on the rotation center C side. In other words, the suction inner portion 740 of the fourth embodiment is not provided with portions corresponding to the suction inner body 711 and the suction inner intermediate portion 713.

That is, the suction inner portion 740 of the fourth embodiment has an arc shape centered on the rotation center C and includes a suction inner recess 742 whose distance from the rotation center C is equal to the distance from the rotation center C to the end of the rotor recess 24 of the rotor 20 in the rotational axis direction. The suction inner recess 742 is formed over the entire region of the suction port in the circumferential direction from the upstream to downstream ends thereof.

The suction inner recess 742 and the upstream end of the suction port are connected at a curved surface of a predetermined radius, and the suction inner recess 742 and the downstream end of the suction port are connected at a curved surface of a predetermined radius.

In the vane pump 704 of the fourth embodiment, the suction inner portion 740 (the first suction inner portion 538 and the second suction inner portion 539 of the inner plate 50 and the first suction inner portion 613 and the second suction inner portion 614 of the outer plate 60) of the suction port includes the suction inner recess 742 depressed toward the rotation center C relative to the curved surface portion 22 of the rotor 20. This shape increases an opening area of the suction port as compared to, for example, a configuration in which a distance from the rotation center C to any point on the suction inner portion 740 in the circumferential direction is the same as the distance from the rotation center C to the curved surface portion 22 of the rotor 20. As a result, the vane pump 704 of the fourth embodiment can have increased suction efficiency as compared to a vane pump that is not formed with the suction inner recess 742.

In the vane pump 704 of the fourth embodiment, the suction inner recess 742 is formed over the entire region of the suction port in the circumferential direction from the upstream to downstream ends thereof. This increases the opening area of the suction port as compared to, for example, a configuration in which the suction inner recess 742 is formed in a part of the suction port in the circumferential direction, and thus can increase suction efficiency.

In the above first to fourth embodiments, the portion of the suction inner recess (e.g., the suction inner recess 722) of the suction inner portion (e.g., the suction inner portion 710) that is most depressed toward the rotation center C is at the same distance from the rotation center C as the distance from the rotation center C to the end in the rotational axis direction of the rotor recess 24 of the rotor 20. However, the present invention is not limited to these embodiments. The portion of the suction inner recess most depressed toward the rotation center C may be depressed closer to the rotation center C than the rotor recess 24 of the rotor 20. This increases the opening area of the suction port further and thus increases suction efficiency.

Fifth Embodiment

A vane pump 705 of the fifth embodiment differs from the vane pump of the above first to fourth embodiments in that portions of the inner plate 50 and the outer plate 60 of the vane pump 705 constituting the first discharge port 4 or the second discharge port 5 are depressed toward the rotation center C relative to the curved surface portion 22 of the rotor 20. Below a description will be given of differences from the vane pump of the first to fourth embodiments. The same structures and functions between the vane pump 705 of the fifth embodiment and the vane pump of the first to fourth embodiments are denoted by the respective same reference numerals and detailed description thereof will be omitted.

FIG. 16 depicts an inner plate 850 of the fifth embodiment as viewed in the one direction and in the other direction along the rotational axis direction.

A first discharge through-hole 855 of the inner plate 850 of the fifth embodiment includes a first discharge inner portion 858 that constitutes a portion of the first discharge port 4 on its side closer to the rotation center C. A second discharge recess 853 of the inner plate 850 includes a second discharge inner portion 859 that constitutes a portion of the second discharge port 5 on its side closer to the rotation center C.

FIG. 17 depicts an outer plate 860 of the fifth embodiment as viewed in the other direction and in the one direction along the rotational axis direction.

A first discharge recess 863 of the outer plate 860 of the fifth embodiment includes a first discharge inner portion 868 that constitutes a portion of the first discharge port 4 on its side closer to the rotation center C. A second discharge through-hole 865 of the outer plate 860 includes a second discharge inner portion 869 that constitutes a portion of the second discharge port 5 on its side closer to the rotation center C.

Since the first discharge inner portion 858 and the second discharge inner portion 859 of the inner plate 850 and the first discharge inner portion 868 and the second discharge inner portion 869 of the outer plate 860 have the substantially same shape, these may be collectively referred to as a “discharge inner portion 800” in the following description. Also, when there is no need to distinguish between the first discharge port 4 and the second discharge port 5, the first discharge port 4 and the second discharge port 5 may be collectively referred to as a “discharge port” in the following description.

FIG. 18 depicts the cam ring 40 and the inner plate 850 as viewed in the one direction.

The discharge inner portion 800 includes a discharge inner body 801 contoured to the shape of the curved surface portion 22 of the rotor 20, and a discharge inner recess 802, which is an example of the second recess, depressed toward the rotation center C relative to the curved surface portion 22 of the rotor 20. The discharge inner portion 800 further includes a discharge inner intermediate portion 803 between the discharge inner body 801 and the discharge inner recess 802.

The discharge inner body 801 has an arc shape centered on the rotation center C, and a distance from the rotation center C to the discharge inner body 801 is the same as the distance from the rotation center C to the curved surface portion 22 of the rotor 20.

The discharge inner recess 802 is formed to connect to an end of the discharge port on the upstream side (upstream end). Taking the first discharge port 4 as an example, a rotational angle of the end of the discharge port on the upstream side (upstream end) is equal to a rotational angle of upstream ends of the first discharge recess 433 and the first discharge recess 443 of the cam ring 40, the first discharge through-hole 855 of the inner plate 850, and the first discharge recess 863 of the outer plate 860, all of which constitute the first discharge port 4, because the upstream ends of these portions all have the same rotational angle. In other words, the discharge inner recess 802 of the first discharge inner portion 858 is formed to connect to the upstream end of the first discharge through-hole 855 of the inner plate 850.

A distance from the rotation center C to a portion of the discharge inner recess 802 that is most depressed toward the rotation center C is equal to the distance from the rotation center C to the end of the rotor recess 24 of the rotor 20 in the rotational axis direction.

The discharge inner intermediate portion 803 is formed to connect the discharge inner recess 802 and a center portion 804 of the discharge inner body 801 located between upstream and downstream ends of the discharge inner portion 800.

The discharge inner recess 802 and the upstream end of the discharge port are connected at a curved surface of a predetermined radius, and the discharge inner body 801 and the discharge inner intermediate portion 803 are connected at a curved surface of a predetermined radius. The discharge inner body 801 and a downstream end of the discharge port are connected at a curved surface of a predetermined radius.

In the vane pump 705 of the fifth embodiment, the discharge inner portion 800 (the first discharge inner portion 858 and the second discharge inner portion 859 of the inner plate 850 and the first discharge inner portion 868 and the second discharge inner portion 869 of the outer plate 860) of the discharge port includes the discharge inner recess 802 depressed toward the rotation center C relative to the curved surface portion 22 of the rotor 20. This shape increases an opening area of the discharge port as compared to, for example, a configuration in which the discharge inner body 801 is formed over the entire region of the discharge inner portion 800 in the circumferential direction and the discharge inner recess 802 is not formed. As a result, the vane pump 705 of the fifth embodiment can have increased discharge efficiency as compared to a vane pump having the discharge inner portion 800 that is not formed with the discharge inner recess 802. In other words, discharge pressure can be reduced in an initial phase of a discharge stroke because the opening area of the discharge port is increased in the initial phase of the discharge stroke. This can suppress backflow of oil from the discharge port into the pump chambers, making it possible to discharge a larger amount of oil in the initial phase of the discharge stroke. This in turn makes it possible to completely discharge air bubbles (air) even if air bubbles (air) are contained in the oil within the pump chambers. As a result, a larger amount of oil can be suctioned in a suction stroke following the discharge stroke.

In the above fifth embodiment, the portion of the discharge inner recess 802 of the discharge inner portion 800 that is most depressed toward the rotation center C is at the same distance from the rotation center C as the distance from the rotation center C to the end of the rotor recess 24 of the rotor 20 in the rotational axis direction. However, the present invention is not limited to this embodiment. The portion of the discharge inner recess 802 most depressed toward the rotation center C may be depressed closer to the rotation center C than the end of the rotor recess 24 of the rotor 20 in the rotational axis direction. This increases the opening area of the discharge port further and thus increases discharge efficiency.

<Modification of the Rotor Recess 24>

In the above first to fifth embodiments, the size of the rotor recess 24 in the rotational axis direction is smaller than the size of the first suction recess 431 and the first suction recess 441 of the cam ring 40 in the rotational axis direction. However, the present invention is not limited to these embodiments.

FIG. 19 depicts a modification of the rotor recess 24 of the rotor 20.

As shown in FIG. 19, the size of the rotor recess 24 in the rotational axis direction may be larger than the size of the first suction recess 431 and the first suction recess 441 of the cam ring 40 in the rotational axis direction. For example, the size of the rotor recess 24 in the rotational axis direction may be increased while the size thereof in the direction toward the rotation center C at the end of the rotor 20 in the rotational axis direction is kept the same as that of the rotor recess 24 of the first to fifth embodiments. This increases the volume of the recess depressed from the curved surface portion 22 toward the rotation center C as compared to that of the rotor 20 of the first to fifth embodiments. This in turn can increase the amount of oil suctioned into the pump chambers, and thus suppress an excessive decrease in the amount of oil suctioned into the pump chambers that may otherwise occur due to the outer periphery of the rotor 20 having the arc-like curved surface portion 22 centered on the rotation center C.

The rotor recesses 24 formed at the respective ends of the rotor 20 in the rotational axis direction may be made continuous with each other. That is, the two rotor recesses 24 may share the same end on the side closer to the outer peripheral surface (curved surface portion 22) of the rotor 20. In other words, both ends of the two rotor recesses 24 on the side closer to the outer peripheral surface of the rotor 20 may be at the center of the rotor 20 in the rotational axis direction. This maximizes the volume of the recess depressed toward the rotation center C from the curved surface portion 22.

<Modification of the Curved Surface Portion 22>

FIG. 20 depicts a modification of the curved surface portion 22 of the rotor 20.

In the above first to fifth embodiments, the curved surface portion 22 of the rotor 20 may be formed with a communication portion 222 depressed from the curved surface portion 22 toward the rotation center C so as to provide communication between the two rotor recesses 24 formed at the respective ends of the rotor 20 in the rotational axis direction. By way of example, the communication portion 222 is formed so as to extend in the rotational axis direction at the center of the curved surface portion 22 in the circumferential direction.

Providing the communication portion 222 communicating the two rotor recesses 24 with each other allows air that collects toward the rotor 20 during rotation by centrifugal force to be guided into the communication portion 222, and this improves efficiency of air discharge into the discharge port in a discharge section. This configuration also improves efficiency of air discharge from the pump chambers, helping suppress fluctuation in pressure and occurrence of noise.

REFERENCE SIGNS LIST

-   1, 702, 703, 704, 705 . . . Vane pump -   2 . . . First suction port -   3 . . . Second suction port -   4 . . . First discharge port -   5 . . . Second discharge port -   10 . . . Rotary shaft -   20 . . . Rotor -   22 . . . Curved surface portion -   24 . . . Rotor recess -   30 . . . Vane -   40 . . . Cam ring -   50 . . . Inner plate -   60 . . . Outer plate -   100 . . . Housing -   110 . . . Case -   120 . . . Cover -   710, 720, 730, 740 . . . Suction inner portion -   712, 722, 732, 742 . . . Suction inner recess -   800 . . . Discharge inner portion -   802 . . . Discharge inner recess 

1. A vane pump device comprising: a rotor configured to rotate under rotational force from a rotary shaft while supporting a plurality of vanes, the rotor including a curved surface portion with an arc shape centered on the rotary shaft, the rotor including a first recess depressed from the curved surface portion toward a rotation center; a cam ring disposed so as to surround the rotor, the cam ring including an inner peripheral surface facing the curved surface portion of the rotor; and a one side member disposed on one end of the cam ring in an axial direction of the rotary shaft so as to cover an opening of the cam ring, the one side member including a second recess depressed toward the rotation center relative to the curved surface portion of the rotor.
 2. The vane pump device according to claim 1, wherein the one side member includes an inner portion that constitutes a portion of a suction port on a side thereof closer to the rotation center, the suction port being configured to suction a working fluid into a pump chamber defined by an outer peripheral surface of the rotor, the inner peripheral surface of the cam ring, and two adjacent vanes of the plurality of vanes, and the second recess is a portion that is a part of the inner portion and depressed toward the rotation center.
 3. The vane pump device according to claim 2, wherein the inner portion of the one side member comprises a portion that is contoured to a shape of the curved surface portion of the rotor, and a portion of the inner portion between the portion contoured to the shape of the curved surface portion and the second recess is contoured to a shape of the inner peripheral surface of the cam ring.
 4. The vane pump device according to claim 2, wherein the second recess of the one side member is formed at a downstream portion of the inner portion in a circumferential direction.
 5. The vane pump device according to claim 2, wherein the second recess of the one side member is formed substantially at a center of the inner portion in a circumferential direction.
 6. The vane pump device according to claim 1, wherein the second recess of the one side member is formed over an entire region of a portion of a suction port on a side thereof closer to the rotation center, the suction port being configured to suction a working fluid into a pump chamber defined by an outer peripheral surface of the rotor, the inner peripheral surface of the cam ring, and two adjacent vanes of the plurality of vanes.
 7. The vane pump device according to claim 1, wherein the cam ring includes a third recess depressed in an axial direction of the rotary shaft from a mating surface of the cam ring for mating with the one side member, the third recess being configured to constitute a suction port, the suction port being configured to constitute a suction path through which a working fluid is suctioned into a pump chamber defined by an outer peripheral surface of the rotor, the inner peripheral surface of the cam ring, and two adjacent vanes of the plurality of vanes, and the first recess of the rotor is formed at a portion of the rotor facing the third recess of the cam ring.
 8. The vane pump device according to claim 7, wherein a size of the first recess of the rotor in the axial direction of the rotary shaft is smaller than a size of the third recess of the cam ring in the axial direction of the rotary shaft.
 9. The vane pump device according to claim 1, wherein the one side member includes an inner portion that constitutes a portion of a discharge port on a side thereof closer to the rotation center, the discharge port being configured to discharge a working fluid from a pump chamber defined by an outer peripheral surface of the rotor, the inner peripheral surface of the cam ring, and two adjacent vanes of the plurality of vanes, and the second recess is a portion that is a part of the inner portion and depressed toward the rotation center. 